The most studied cosmic explosion mystery in human history

It is the most studied cosmic explosion in human history. Supernova 1987A, as its name suggests, suddenly appeared in the night sky as a bright point of light in 1987, becoming the first star explosion since 1604 that humanity could see with the naked eye.

For the past three decades, astronomers have been searching for exactly what was left of the exploded star after that explosion. Now comes an international team of astronomers In the trade magazine Sciences Finally, with the word of redemption. The explosion produced a pulsar, they write: a densely packed, rapidly rotating stellar body emitting powerful streams of radiation, a sort of cosmic version of a lighthouse.

A cloud of cosmic debris

Such a pulsar – a type of neutron star – was, however, the most likely endpoint of this starburst. Forces from the supernova compress the remains of the exploded star. If the original star had less mass, gravity compresses the rest less tightly after the explosion, giving rise to a neutron star; If it had a little more mass, the end result would be a black hole. Accordingly, astronomical models predicted a neutron star as the end point. However, the existence of a black hole, or even more exotic options, cannot be ruled out, so astronomers have speculated wildly in recent decades.

What remains of SN 1987A has so far been hidden from the prying eyes of even the most powerful telescopes. The star, or black hole, was surrounded by a cloud of cosmic debris that exploded into the space surrounding it during the explosion.

“A very long saga”

Astronomer Ralf Wijers of the University of Amsterdam, who was not involved in the research, says it is “very nice” that the remnants of SN 1987A have finally been found. “This is the end of a very long saga. In recent years there have been new studies claiming that they saw something and then had to correct it later. But this time, the analogy is very convincing.”

By the way, Wegers is cautious about whether what the researchers have now seen is actually a neutron star. “It is very difficult to tell the difference between a pulsar and a black hole. I noticed that the authors keep calling it a ‘compact object’ in their article. They are clearly not 100% sure yet that it is actually a neutron star.”

The fact is that this compact object can be seen at all because astronomers have had the James Webb Space Telescope at their disposal since 2022. “It is much more sensitive to wavelengths of light, and has a much greater spatial resolution,” he says. “There is currently no other instrument that can provide this observation.”